Long Island Marine Surveyor

Telephone 631 589-6154  Fax 631 563-3758

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Long Island Marine Surveyor 631-589-6154

Delaminated Area of Hull below waterline

Delaminated fiberglass  is caused by the separation of the layers of a fiberglass laminate.  Water penetration is generally the cause of Delaminated fiberglass below the waterline of a vessel.  Poor construction is another cause of Delaminated fiberglass.  Water penetration is the most destructive of these two.

To understand Delaminated fiberglass you must understand the construction of a vessel.  Boats are constructed of wood, fiberglass (also known as glass reinforced plastic), and stainless steel.  The fiberglass which most boats today are made from is a mixture of fibers of glass (cloth & Mat) and resin (a plastic that holds the glass fibers together).

Hull Delaminated Fiberglass

The hull of a fiberglass vessel often has wood or fiberglass stringers that run through the vessel forward to aft.  These stringers give the vessels hull its strength and structural stability.  An impact with a underwater submerged object can cause structural damage to the hull below the waterline.  Any damage to the stringers will continue to cause further damage to other areas of the vessel since the hull no longer has that needed stability.  Areas of delaminated fiberglass are often found where a collision has occurred below the waterline.  Once water has entered fiberglass it will continue to cause havoc with each winter that passes.  Water once frozen becomes ice.  Since ice occupies more volume that water that ice begins to push apart ever further that delaminated fiberglass section.  Of course the further a section is delaminated the more water is allowed to enter.  To make matters worse once water has entered a delaminated section of fiberglass it becomes trapped unable to evaporate.  This trapped water forms an acidic solution, and yes this acidic solution further disintegrates  the resin which holds the fiberglass together.  Once an area of fiberglass has delaminated it only gets worst.  How quickly an area will disintegrate will depend on where it is located, what originally caused the damage, the size of the area, the construction of the vessel and how long the area has been delaminated.

Blistering of fiberglass below the water line will cause delaminated fiberglass often under the blistering.  Blisters can be small when first appearing often the size of a goose bump on the gel coat of a boat.  Such small blisters are often invisible to the  eye and would require a moisture meter to be found.  Larger blisters can be the size of a half dollar and are easily found.  What makes finding blisters an art is the various layers of bottom paint covering them.  This paint is often cracked peeling and blistered itself.  It is often easier to find blisters on an unpainted hull that one recently painted, and the older the bottom paint the easier to spot blisters.  Four, five, six or more layers of bottom paint can hide a lot of blisters.  The causes of blistering are varied and you will get as many explanations as you have experts.  A moister meter is the preferred tool to find blistering but a small plastic hammer will work as well in the correct hand.  

Delaminating of Deck Areas

Decks of fiberglass boats are constructed of fiberglass with a wood core.  Fiberglass itself is flexible and very heavy.  Fiberglass is also expensive when compared to wood.  So a good amount of all fiberglass boats are constructed of wood.  Wood is used to give strength to fiberglass, wood gives fiberglass it structural stability.  This is accomplished through a technique called sandwich construction.  Sandwich construction sandwiches a wood core material between top and bottom layers of fiberglass.  This core material must remain water tight.  Should water enter the wood core two things will begin to happen.  First the water will begin to rot the wood.  Second the water when tuned to ice will push apart the fiberglass top and bottom layers that encase it.  Areas of the deck that become delaminated loose the structural stability and strength.  A spongy feel is noted when walking on these areas.  When delaminated deck areas are chronic a series of cracks will present themselves over the delaminated areas.  Rectifying such a situation may require replacement of the core material, a considerable expensive.

Stainless steel and aluminum are often used on fiberglass boats for stanchions and railing, ladders, lights, lifelines, anchor windlass, horns and many other items that are screwed into the deck wooden core.  As a boat matures the caulking used to secure the items often deteriorates allowing water to enter the wood core.  How serious this condition has become varies.

Key Benefits of a survey

See the section on surveyor fees for a more detailed cost of a second visit.

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